Ignition harness



Dec. '12, 1939. H. c. HILL 2,183,020

IGNITION HARNESS Filed April 15, 1939 2 Sheets-Sheet l HENRY c. HILL ATTORNEY Dec. 12, 1939. H. c. HILL 2,183,020

IGNITION HARNESS Filed April 15, 1939 2 Sheets-Sheet 2 R ssenzm'm. l TUBE l-ELBOW BRIDGE counun F 4 1 imb- 1:-- L I J-"25 8 L FLEXIB E TUBE usmg R R #4174420 rmauz'ro LEFT R kw! INVENTOR I HENRY c. HILL L v ATTORNEY Patented Dec. 12, 1939 PATENT OFFICE IGNITION HARNESS Henry 0. Hill, Montclair, N. 1., aaaignor to Wright Aeronautical Corporation, a corporation of New York Application April 15, 1939, Serial No. 268,149

10 Claim.

This invention relates to ignition wiring for internal combustion engines and relates particularly to an ignition harness assembly adapted for use with radial cylinder aircraft engines.

5 A problem of ignition wiring harness either with or without radio shielding for radial cylinder engines is one which involves a consideration of adapting the harness system to the engine with a minimum of interference of the assembly 10 with other engine parts, combined with an effort to simplify the harness assembly itself so that the parts thereof may be readily disassembled and assembled and so that the utmost simplicity obtains in leading the wiring from the sparkplugs 15 of the individual cylinders to the magnetos of the engine which are conventionally located on the rear part thereof in laterally spaced relation. Since virtually all aircraft engines are equipped with dual ignition, the arrangement of the igni- 20 tion wiring involves a crossing over of alternate wires from one side of the engine to the other so that each cylinder is provided with an ignition impulse from both the right and left magnetos. In the prior art, numerous arrangements have 25 been suggested for the wiring arrangement, these usually involving asymmetrical ignition manifolds, one serving four of the nine cylinders and the other serving five of the nine cylinders, also, arrangements have been proposed and used in which a single substantialy circular manifold is used in which all of the ignition wiring is threaded. These prior types have certain limitationsthe asymmetrical system requires the design,

'manufacture, and service stocking of two differ- 35 ent assemblies while the unitary manifold system is diflicult to assemble on the engine, does not lend itself to compact packaging, and involves sharp bends in the ignition cable reducing its efiiciency and permitting of rapid deterioration.

In the subject invention, I propose the use of a pair of manifold assemblies for an engine each of which is identical with the other, the assemblies to be so arranged as to each serve precisely one-half the number of sparkplugs with 45 which the engine is equipped. In this connection, radial cylinder engines have an odd number of cylinders, ordinarily, nine. ignition, each manifold will carry the same number of cables as there are cylinders, the odd 50 cable in each harness unit serving one cylinder of the engine from the right-hand and left-hand magnotos, while other pairs of cables in each Hence, with dual As a further object of the invention, I contemplate the provision of magneto distributor housings and a cross-over assembly between the magnetos whose position is fixed relative to the engine, the magneto housings being so arranged 5 as to permit of timing adjustment of the magnetos therebeneath. A further object of the invention is to provide a novel means of detachably securing the ignition harness to the engine without disturbing the structural integrity of the engine itself.

Still another object comprises the arrangement and marking of the wiring in the harness units so that the cylinder wires may be readily identified for connection to the proper magneto distributor units.

Further objects of the invention will become apparent in reading the annexed detailed description in connection with the drawings in which:

Fig. 1' is a front elevation of a portion of a radial cylinder engine, showing the identical ignition harness units;

Fig. 2 is a plan of part of the conduits and housings comprising the shielding assembly;

Fig. 3 is an enlarged section on the line 3-3 of Fig. 1;

Fig. 4 is a rear elevation of a typical magneto showing the housing by which the magneto is mechanically joined to the harness assembly and,

Fig. 5 is a wiring diagram of the harness assembly shown with relation to the several components of the harness conduits.

Referring to Fig. 1, an engine crankcase is indicated at It, this having cylinder decks I l upon which the engine cylinders are mounted, three of such cylinders being shown at l2, l3 and it, these numbers respectively designating cylinders Nos.

1, 2 and 9 of a nine cylinder engine. According to conventional practice, each cylinder is provided with two sparkplugs such as l5. Ignition wires l6 lead from all but the top cylinder to identical manifolds indicated at H, these comprising segmental tubular members having radially extending ferrules through which the wires 5 I6 pass. To the upper end of each manifold I1 is swivelly secured, as by a union nut is, an elbow 20 through which the several wires I 6 pass longitudinally of the crankcase. Each elbow 20 is provided with a ferrule II for reception of a wire 22 serving the top cylinder II. It will be noted that the ferrules 2| are offset from the plane of symmetry ofthe elbows 20 but this offset is the same in both the right and left hand elbows so that the right and left hand parts 20 are identical.

This offset of the ferrules 2| is convenient to enable the wires 22 to be led to the sparkplugs of the cylinder |2 in a direct and convenient manner, the extending portions of the cables 22 being of identical length.

To the rearward ends of the elbow conduits 20, flexible conduits 24 are secured by union nuts 24', these conduits leading the enclosed ignition wires to identical housings 25 each secured to a mounting pad 25 on and concentric with the axis of mounting and rotation of magnetos 21. The connection from each conduit 24 to each housing 25 is made through a suitable fitting 28. The rearward ends of the housings 25 are open (Fig. 4) and over these openings elbows 29 are secured, facing toward one another from respective magnetos, and joined by a bridge conduit 30 which is flexible as shown but may likewise be of solid tubing.

The housings 25 carry circumferentially slotted arcuate pads 3| in fitting engagement with the arcuate pads 26 of the magnetos, the housings being secured to the magnetos through the slots by cap screws 32. By this construction, the magnetos 21 may be adjusted for timing about their centers of rotation, without disturbing the position of the housings 25 by loosening the cap screws 32 whereby the pad 25 of the magneto moves beneath the housing 25, after which the cap screws 32 may be secured.

In mounting the manifolds upon the engine casing, clips 33 are used, the ends of these clips being permanently secured beneath the heads of bolts 34 by which the crankcase parts are held together. The central portion of each clip 33 is raised from the surface of the crankcase Ill and is so curved as at 35 as to receive the manifold in fitting engagement. A clamp 31 such as a hose clamp, is then wrapped around the manifold and clip portion 36 securing one to the other. By this construction, the manifold assembly may be readily removed from the engine without disturbing the crankcase bolts 34, the clips 33 being left upon the engine after the manifolds are removed.

Now, it will be realized that the use of two identical manifold assemblies presents certain difllculties in the wiring of the several sparkplugs to the right and left hand magnetos of the engine. This is taken care of in a manner which is best shown in Fig. which represents a plan of the harness system with particular emphasis on the wiring but with the several harness parts I1, 24, 25 and 30 shown in dot-dash lines. It will be seen that the wires 22 from the cylinder |2 (No. 1 top cylinder) pass from the elbows 20 rearwardly through the conduits 24 to respective housings 25 where the wires are cut to a length appropriate to connect with the magnetos these bearing the number I without right or left indication. Such indication is unnecessary since the wire is automatically positioned for the proper magneto. The other wires, however, according to whether the harness unit is used on the right or left side of the engine, must pass alternately to the same side and opposite side magnetos. Accordingly, all of the other wires B emanating from the rear end of the conduit 24, are left sufiiciently long to be threaded through the bridge conduit 30. to the opposite side magneto, but markers are provided so that alternate wires may be cut off for connection to the magneto on the same side while the long wires may be passed through the bridge conduit for connection to the magneto on the other side. To simplify identification of these long wires, each one carries spaced markers, one marker such as 40 being relatively close to the conduit 24 while the other marker 4| is remote therefrom, being diaposed at such a point along the wire that the marker will be visible after the wire has been threaded through the bridge conduit 30. In assembling the system the following procedure would be observed: Having secured the harness units I1, 20, 24 and 25 to the engine, and having drawn the wires through respective elbows 23, the assembler may deal first with the left hand magneto and will identify markers 4| as 5R, IR, IR and SR, threading these wires across to the right hand magneto through the bridge conduit 34. The remaining wires he may cut off just beyond the inner markers 40 which will leave five short wires marked 6L, 1L, 8L and BL to be connected to the appropriate distributor terminals.

Giving his attention to the right hand magneto, he will segregate wires whose markers 4| designate 2L, 3L, 4L, and SL threading these through the bridge conduit 30 toward the left hand magneto. Then, he may cut off the remaining wires beyond the markers 40 leaving wires 2R, 3R, 4B and 5B for connection to the appropriate terminals of the right hand magneto. Then, the connections of those wires which have been threaded through the bridge conduits may be completed to the terminals of the appropriate magnetos, these several long wires being of the proper length so that no further cutting is necessary.

The above numbering assumes that the distributor numbers correspond to the cylinder numbers, which may not necessarily obtain in practice, since distributor numbers may be sequential in firing order while the cylinders fire 1 3 5 7 9 2 4 6 8. However, the proper arrangement of markers to meet this situation is readily made during manufacture.

Having once installed the harness assembly, the several wires are all appropriately marked adjacent the distributor terminals so that in servicing the engine no confusion may exist in making the proper connections. The alternate markers 40 which are on wires crossing over to the opposite magnetos are of no moment in making the connections to the one magneto since there are no wire ends available.

The organization above described has made no particular reference to the problem of radio shielding since the structure described is usable without shielding. However, the inclusion of metallic radio shielding upon the several structural components involved in the harness assembly is considered to be within the purview of the invention.

The organization herein disclosed permits of the following improvements over prior structures and obtains the advantages enumerated: (a) the elimination of special shapes of components in order to clear engine accessories; (b) elimination of complicated tube bends; (c) division of the manifold into two units permits of smaller manifold diameter on the front of the engine, bringing it closer to the engine casing; (d) reduction in the number of soldered or brazed joints; (e) increase in the ease of threading wires through the system and elimination of sharp bends in the wires by which there is less possibility of wire breakdown due to abrasion of insulation; (j) shortening of the individual ignition wires allowing of improved electrical characteristics; (g) permits removal of one-half of the manifolding without disturbing the other half; (h) permits replacement or removal of manifolding without the necessity of removal of other engine attachments; (i) the half units ofthe harness are identical permitting of economy in manufacture, and facilitating shipping and stocking of service parts; (1) the manifold attachment to the crankcase by the use of clamps eliminates the necessity for removing crankcase bolts during assembly and disassembly of the harness; (is) the magneto housings for both magnetos are identical, promoting the advantages above outlined; (l) the simplicity of the design indicates the possibility of using materials superior to those which have been used in the past for radio shielding-that is, the several conduits and housings may be readily fabricated from stainless steel instead of the conventional brass.

While I have described my invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding my invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. I aim in the appended claims to cover all such modifications and changes.

What I claim is:

1. An ignition harness for a radial cylinder engine comprising identical segmental conduits in looking-glass symmetry secured to the engine case concentric therewith, the conduits having an identical plurality of radial openings and ferrules thereat, ignition wiring threaded from the engine cylinder through said ferrules to the adjacent ends of said conduits whence the wiring emanates, and identical conduit elbows through which the wires pass, swiveled upon the conduits to lead the wiring axially over the engine case.

2. In a radial cylinder engine having an odd number of coplanar cylinders, and having a pair of spark plugs in each, an ignition wiring harness on one end of the engine casing comprising identical concentric segmental conduits disposed opposite one another, said conduits each having ferrule outlets indentically disposed and of a number equal to half the number of spark plugs less one, identical elbows swiveled to the adjacent conduit ends each having a single ferrule outlet, said elbows extending axially of the engine to the engine ignition supply.

3. In an ignition wiring harness for a dual ignition radial cylinder engine including ignition supply units laterally spaced, a pair of identical harness units each adapted to serve half the sparkplugs of the cylinders; each comprising a segmental conduit secured to the engine case, outlet ferrules extending radially outward from the conduit, a swivel elbow conduit at one end of the segmental conduit, and ignition wires threaded through respective ferrules and the conduits.

4. In an ignition wiring harness for a dual ignition radial cylinder engine including ignition supply units laterally spaced, a pair of identical harness units each adapted to serve half the spark plugs of the cylinders; each comprising a segmental conduit secured to the engine case, outlet ferrules extending radially outward from the conduit, a swivel eblow conduit at one end of the segmental conduit, and ignition wires threaded through respective ferrules and the conduits, said wires being identical for each harness unit and having markings spaced apart on those wire ends which extend from the elbow conduit, those markings closest to the conduit end identifying wires adapted to be cut off for connection to the ignition supply unit on that side of the engine nearest the harness unit and those markings farthest from the conduit end identifying wires adapted to be connected to the ignition supply unit on the opposite side of the engine from the harness unit.

5. A harness unit for use on either side of a dual ignition radial cylinder engine having laterally disposed ignition current supply units comprising a conduit having wire outlets opposite respective engine cylinders, wires in said conduit each threaded through one said outlet and extending in a group from one end of the conduit, a first plurality of markers, one on each wire, close to theconduit end and identifying alternate wires adapted to be cut off and connected to the ignition supply unit on the same side of the engine as the conduit, and a second plurality of markers one on each wire and remote from the conduit end and identifying alternate wires adapted to be connected to the ignition supply unit on the opposite side of the engine from the conduit.

6. A harness unit for use on either side of a dual ignition radial cylinder engine having laterally disposed ignition current supply units comprising a conduit having wire outlets opposite respective engine cylinders, wires in said conduit each threaded through one said outlet and extending in a group from one end of the conduit, a first plurality of markers, one on each wire, close to the conduit end and identifying alternate wires adapted to be cut off and connected to the ignition supply unit on the same side of the engine as the conduit, and a second plurality of markers one on each wire and remote from the conduit end and identifying alternate wires adapted to be connected to the ignition supply unit on the opposite side of the engine from theconduit, housing units on the ignition supply units, couplings on the conduits for attachment to the housings, and a crossover conduit connecting said housings through which the wires carrying said remote markers are threaded from respective harness conduits to opposite ignition supply units.

7. In an engine having cap screws let into a face thereof, bridge elements having ends secured to the engine by adjacent cap screws and having an intermediate portion raised from contact with the engine, a tubular element overlying the bridge element, and an adjustable clamp wrapped around said elements securing one to the other.

8. In an attachment for an ignition wire manifold to an engine casing, a strip element permanently secured to the engine and having a portion raised from the engine surface, said manifold overlying said raised portion, and an adjustable clamp wrapped around said manifold and raised portion securing the manifold thereto.

9. In an engine, a rotationally adjustable ignition supply unit having a concentric mounting pad thereon, a wire housing fitted to said pad, said housing having elongated slots, attaching means passing through said slots and engaging the unit, said unit being thereby rotatably ad justable with respect to the housing as well as to the engine, a wire manifold extending from said housing, an ignition wiring extending from said unit through said housing and into said manifold,

10. A shielded ignition harness for radial cylinder aircraft engines adapted for dual ignition and having spaced rotationally adjustable distributor units comprising a pair of identical manifold units of segmental form on opposite sides of and concentric with the engine, clips permanently secured to the engine, adjustable clamps wrapped around and securing said clips and manifolds, radial ferrules spaced along the manifolds, a plurality of conductors threaded through said ferrules 'and manifolds, identical elbow conduits swiveled on ends of respective manifolds through which the wiring passes, said conduits being swiveled to permit of adjustment thereof to asymmetry of the engine parts and fittings, wire housings adjustably secured to respective distributor units so organized as to remain in fixed position as the respective units are moved in adjustment, a bridge conduit between said housings; the individual wiring in both manifolds and elbow conduits being initially sufficiently long to be threaded through a housing and bridge conduit to the other housing, and spaced markers on each wire respectively close to and remote from the elbow conduit end from which it emanates, the marker close to the conduit identifying the wire for connection to the distributor unit on the same side of the engine as the conduit and the marker remote from the conduit identifying the wire for threading through said bridge conduit and connection to the distributor on the opposite side of the engine.

HENRY C. HILL. 

